Last updated on March 10, 2026
New emissions mandates are reshaping the maritime industry. Here’s what rules apply—and how operators are preparing for compliance.
Regulations targeting maritime emissions are accelerating around the world. From international climate mandates to aggressive local air quality rules, the pressure is rising for shipping companies to cut pollution both at sea and in port.
Maritime emissions regulations refer to international, regional, and local laws that limit greenhouse gases (GHGs) and air pollutants from ships, including CO₂, NOₓ, SOₓ, and particulate matter (PM). These rules govern fuel quality, vessel efficiency, at-berth emissions, and carbon pricing.
This urgency reflects the scale of the challenge: maritime shipping moves over 80% of global trade and, in the process, contributes nearly 3% of total greenhouse gas (GHG) emissions. At the same time, vessels release high volumes of sulfur oxides (SOₓ), nitrogen oxides (NOₓ), and particulate matter (PM). These pollutants harm the air quality and public health of frontline port communities around the world.
For operators, ports, and logistics stakeholders, understanding which emissions rules apply — and how to comply — is essential to building resilient, future-ready operations.
Why are maritime emissions a regulatory priority?
Maritime emissions are facing increasing scrutiny due to their outsized impact on both global climate and local air quality.
Ship emissions primarily come from:
- Main and auxiliary engines, which burn bunker fuel while ships are underway or idling in port
- Boilers and onboard power systems, especially active during cargo handling
- Fuel storage and transfer systems, which can leak or vent harmful vapors
These systems release:
Carbon dioxide (CO₂)
The primary GHG driving global climate change.
Nitrogen oxides (NOₓ)
Pollutants that contribute to primary GHGground-level ozone and smog, leading to respiratory problems.
Sulfur oxides (SOₓ)
Compounds that react in the atmosphere to form fine particles, harming air quality and causing acid rain that primary GHG ground-level ozone and smogendangers aquatic species.
Particulate matter (PM)
Microscopic particles (dust, dirt, soot, smoke, etc., which can be made up of hundreds of different chemicals) that penetrate deep into the lungs and bloodstream, causing long-term health effects, are also called particle pollution.
Around the world, prolonged exposure to ship emissions has been linked to higher rates of asthma, lung disease, and cardiovascular conditions. The most severe health impacts are concentrated in coastal and port communities. Environmentally, these pollutants accelerate climate change, damage coastal ecosystems, and contribute to ocean acidification.
These pressures are driving a rapid policy shift, and operators must act now to keep pace.
Global and regional regulations for maritime emissions
The rules governing maritime emissions span from international treaties to local enforcement. To understand which regulations apply to your fleet or operations, start by identifying where your vessels sail, what types of ships you operate, and which ports you call on regularly.
What Is the IMO’s Role in Regulating Maritime Emissions?
The International Maritime Organization (IMO) is the UN body that oversees global shipping standards. Through the MARPOL convention (formally known as the International Convention for the Prevention of Pollution from Ships), the IMO sets international rules for emissions, fuel quality, and vessel efficiency.
IMO GHG Strategy
This climate plan targets a 20-30% reduction in total shipping emissions by 2030, and full net-zero emissions by 2050. It’s a global push toward cleaner fuels and smarter operations.
What Is MARPOL Annex VI?
This foundational regulation limits air pollutants from ships and establishes Emission Control Areas (ECAs) where stricter standards apply. It also underpins newer efficiency measures, including:
EEXI (Energy Efficiency Existing Ship Index)
A one-time certification evaluating the design efficiency of existing ships. Required for compliance under IMO regulations.
CII (Carbon Intensity Indicator)
An annual measure of a vessel’s carbon emissions per unit of cargo and distance traveled. Affects a ship’s operational rating and must improve year over year to remain compliant.
What Is California Doing to Reduce Port Pollution?
California enforces some of the world’s strictest maritime air quality rules through the California Air Resources Board (CARB).
CARB’s 2020 At-Berth Regulation requires ocean-going vessels docked at California’s busiest ports to significantly reduce at-berth emissions. The regulation has been implemented in phases, beginning in 2023 with container ships. Requirements expanded in 2025 to include roll-on/roll-off vessels statewide and tanker vessels calling at the Ports of Los Angeles and Long Beach. By 2027, at-berth requirements will apply to tanker vessels at all California terminals.
What Emissions Solutions Qualify Under CARB Rules?
Emissions solutions that qualify under CARB rules include shore power systems or a CARB-verified Capture and Control Emissions Control System (CAECS), like STAX. By 2027, it is estimated that this rule will deliver a 90% reduction in pollution.
What Maritime Emissions Rules Apply to European Ports?
European authorities have converted international climate standards into binding regional law.
European Union Emissions Trading Scheme (EU ETS)
As of 2024, the EU began applying its EU ETS to maritime shipping. This means that large ship operators need to purchase allowances based on their CO₂ output, much like factories and power plants already do. It’s a financial incentive to cut emissions fast.
United Kingdom (UK ETS and Maritime Decarbonisation Strategy)
From 2026, the UK will require ship operators to purchase emissions allowances under the UK ETS, aligning with similar EU measures. In parallel, the UK Government has launched a comprehensive Maritime Decarbonisation Strategy, targeting a 30% reduction in lifecycle GHG emissions from domestic maritime by 2030 (relative to 2008), rising to 80% by 2040 and net-zero by 2050. The strategy includes a proposed requirement for zero or near-zero emissions from vessels at berth, supported by a call for evidence on Net Zero Ports.
Significant investment is also being channeled into zero-emission vessels and green port infrastructure through initiatives like the Clean Maritime Demonstration Competition, which is supporting STAX’s PortZero initiative to demonstrate carbon and air pollution capture from berthed vessels. An established leader in the U.S., STAX is actively working to operate internationally, with a potential £38 million investment to deploy emissions capture and control technology across UK ports.
How Do Asian Ports Handle Ship Emissions?
Asian ports manage ship emissions through fuel standards, emission control zones, and infrastructure investment.
China’s Domestic Emission Control Areas (DECAs)
China has established DECAs in major port regions. These require the use of 0.5% sulfur fuel within 12 nautical miles and 0.1% sulfur fuel at berth in key ports. A national carbon trading scheme for shipping is also being considered.
Singapore’s Decarbonization Blueprint
Singapore is not yet part of an ECA (Emission Control Area) but is a global leader in decarbonization research and development. This roadmap seeks to achieve net-zero emissions for Singapore’s port terminals by 2050.
In response to these evolving regulatory demands, operators are rethinking how ships are fueled, equipped, and run—adopting new strategies to stay compliant and competitive.
How are ports and operators meeting evolving regulations?
Ports meet clean air standards through a combination of technologies and operational measures:
Alternative fuels
To cut emissions at the source, many shipping companies are transitioning away from traditional bunker fuels toward cleaner alternatives.
- Liquefied Natural Gas (LNG): Widely adopted but still emits methane, a potent GHG.
- Methanol: Produces lower emissions and is easier to handle than LNG. It can be made from renewable sources, though its most current supply comes from fossil fuels.
- Ammonia and hydrogen: Zero-emission fuels but face scalability and safety hurdles.
Exhaust treatment technologies
When cleaner fuels aren’t an option, or to add a layer of compliance, many vessels are installing systems that treat emissions before they’re released.
- Scrubbers: These technologies remove sulfur oxides from exhaust gases. Open-loop scrubbers discharge wastewater into the ocean, while closed-loop systems treat and reuse it onboard.
- Carbon capture systems: These systems aim to trap CO₂ emissions onboard before they escape into the atmosphere.
Operational efficiencies
Operators are also turning to smarter practices that cut emissions without requiring major equipment changes.
- Slow steaming: By simply reducing vessel speed, this technique cuts fuel use and emissions.
- Route optimization software: Minimizes unnecessary engine hours.
Shore power (cold ironing)
Shore power, also known as cold ironing, is the process of connecting a ship to land-based power grids while docked. This allows vessels to shut off their diesel generators and continue running onboard systems without producing emissions during port stays. However, shore power has limitations: it requires significant infrastructure investment at ports, compatible onboard equipment, and a stable power grid. Additionally, it only reduces emissions while the vessel is docked, and does not eliminate emissions from boilers.
Emissions capture and control solutions
Emissions capture and control systems are technologies that trap and treat engine exhaust in real time, filtering harmful pollutants before they’re released into the environment. Unlike shore power, these systems operate independently of the power grid. Solutions like STAX connect directly to a vessel’s exhaust stack, helping operators meet regulatory requirements without costly retrofits or schedule disruptions.
While many solutions are still evolving—with limitations around cost, infrastructure, or readiness—emissions capture and control technologies offer an immediate path to compliance. STAX reduces emissions today, bridging the gap to a clean-air future as the industry transitions to more sustainable fuel alternatives.
How Do Ports Prepare for Future Emissions Regulations?
Compliance is fast becoming a non-negotiable aspect of shipping operations. To navigate this, and prepare for future emissions regulations, ports and vessel operators can embrace solutions like emissions capture and control that enable sustainable operations without compromising productivity or uptime.
STAX helps ports and carriers navigate regulatory complexity through turnkey emissions capture systems, built to meet today’s toughest requirements and tomorrow’s evolving standards.
Help your team achieve emissions compliance efficiently and effectively. Learn more about STAX’s technology.
